Python入门笔记：列表

用括号括[]起来，用逗号,分隔其中的元素。

bicycles = ['trek', 'cannondale', 'redline', 'specialized']
print(bicycles)
print(bicycles[0])
print(bicycles[1])
print(bicycles[2])
print(bicycles[3])
print(bicycles[-1])
print(bicycles[-2])
print(bicycles[-3])
print(bicycles[-4])

负数索引表示倒数第几个元素。

向列表添加元素
list.append(something) #往list末尾新增something
list.append(n, something) #往list的第n个位置添加something

bicycles = ['trek', 'cannondale', 'redline', 'specialized']
print(bicycles)
bicycles.append('suzuki')
print(bicycles)
bicycles.insert(2, 'ducati')
print(bicycles)

删除列表元素
del list[n] #删除list的第n个元素
poped = list.pop(n) #删除list的第n个元素，n缺省表示删除末尾元素，poped存放被删除的元素
list.remove(something) #删除list中第一个值为something的元素

bicycles = ['trek', 'cannondale', 'redline', 'specialized', 'redline', 'ducati' ]
print(bicycles)
del bicycles[2]

bicycles = ['trek', 'cannondale', 'redline', 'specialized', 'redline', 'ducati' ]
print(bicycles)
poped = bicycles.pop()
print(bicycles)
print(poped)

bicycles = ['trek', 'cannondale', 'redline', 'specialized', 'redline', 'ducati' ]
print(bicycles)
poped = bicycles.pop(1)
print(bicycles)
print(poped)

bicycles = ['trek', 'cannondale', 'redline', 'specialized', 'redline', 'ducati' ]
print(bicycles)
bicycles.remove('redline')
print(bicycles)

排序
list.sort() #对list按字母顺序排列a-z
list.sort(reverse=True) #z-a
sorted(list) #返回排序好的列表a-z,不改变list的值
sorted(list, reverse=True)

bicycles = ['trek', 'cannondale', 'redline', 'specialized', 'redline', 'ducati' ]
print(bicycles)
print(sorted(bicycles))
print(bicycles)
print(sorted(bicycles,reverse=True))

print(bicycles)
bicycles.sort()
print(bicycles)

bicycles = ['trek', 'cannondale', 'redline', 'specialized', 'redline', 'ducati' ]
print(bicycles)
bicycles.sort(reverse=True)

列表倒序
list.reverse() #倒序list

bicycles = ['trek', 'cannondale', 'Redline', 'specialized', 'redline', 'ducati' ]
print(bicycles)
bicycles.reverse()
print(bicycles)

len(list) #返回list的长度

bicycles = ['trek', 'cannondale', 'Redline', 'specialized', 'redline', 'ducati' ]
print(bicycles)
print(len(bicycles))

遍历列表

magicians = ['alice', 'david', 'carolina']
for magician in magicians:
    print(magician.title() + ", that was a great trick!")
    print("I can't wait to see your next trick, " + magician.title() + ".\n")
print("Thank you, everyone. That was a great magic show!")

用缩进区分代码块

list(something) #将something变为列表
range(a,b,c) #从a到b并不包含b，步长为c，默认为1

for value in range(1,5):
    print(value)
print(list(range(1,5)))
print(list(range(2,10,2)))
print(list(range(2,11,2)))

squares = []
for value in range(1,11):
    squares.append(value**2)
print(squares)

min()
max()
sum()
用列表解析创建squares

squares = [value**2 for value in range(1,11)]
print(squares)

列表切片
和matlab类似，但步长只为1.

复制列表
直接看例子，就是不能用等号直接赋值

m = list(range(2,12))
print(m)
n = m[:]
print(n)
m.append(1234)
n.append(7890)
print("m = ")
print(m)
print("n = ")
print(n)

n = m
m.append(56)
print("m = ")
print(m)
print("n = ")
print(n)
n.append(1029)
print("m = ")
print(m)
print("n = ")
print(n)

元组
和列表类似，只不过用()括起来。
元组中的元素不可修改，不过整个元组的值可以改变。
只有一个元素的话要在末尾加,否则会变成单一的变量，非元组。

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Reference
[美]Eric Matthes著，袁国忠译. Python编程从入门到实践[M]. 北京：人民邮电出版社. 2016.7.